cellio | daf bit: Yevamot 109

(Today's daf is 110.)

The g'mara is discussing learning torah and observing it. R. Papa says: torah says "that you may learn them (mitzvot) and observe them", so he who is engaged in observance is also regarded as engaged in study (he had to learn them), but he who is not engaged in observance is not regarded as engaged in study. (Yes there is a logical fallacy there. No it is not addressed here.)

Another teaching: Who rivets himself to the word of the halacha brings evil upon himself -- this refers to a judge who, when a lawsuit is brought before him and he knows the halacha of a related (but not identical) case, even though he has a teacher, does not go to that teacher to inquire but simply judges the case based on the other halacha. Such a judge brings evil upon himself according to R. Shmuel b. Nachmani in the name of R. Yonatan, who said a judge should always regard himself as if he had a sword lying between his thighs and Gehenna was open beneath him. (109b)

The logical fallacy in that first one could be resolved thus: if one has truly studied torah, he will come to an inevitable conclusion and come to follow it. I don't know if that was considered obvious enough to R. Papa that it need not be stated.